We examined 1,849 consecutively admitted premature infants weighing 2000 gm or less at birth for retrolental fibroplasia (RLF). Proliferative RLF was diagnosed frequently in low birth weight infants who were more likely to survive with modern neonatal intensive care. Cicatricial RLF was more likely to result from proliferative RLF and to be more severe in lower birth weight infants, but most affected eyes retained useful vision. Comparison of cases diagnosed over the 20 years of this study suggest that cicatricial RLF in recent years is less likely to result in severe visual disability. Improving survival rates for lower birth weight infants mandate continued surveillance for RLF and study of improved oxygen monitoring techniques.